Apollo vet Sy Liebergot shows Ars how NASA got men safely to the Moon and back.

Failure is, famously, not an option

The mission would become known as NASA's "finest hour." It started ignominiously enough, with no one really paying attention. Apollo 11 and 12 had successfully landed without anyone getting blown up or lost in space. Landing on the Moon had become routine in the eyes of the public, so the live television coverage of all aspects of the mission which had filled the previous two manned Apollo flights was absent. No one was watching.

The death of another Apollo crew... would likely have spelled an end to Project Apollo and potentially NASA's entire manned program.

That changed about 56 hours into the mission, when a routine order to activate a stir-fan in one of the Service Module's oxygen tanks resulted in a spacecraft-crippling explosion. During the long coast between the Earth and the Moon, the slush liquid oxygen in the tanks would separate into layers, and getting an accurate reading on the tank's fill level became difficult. To get around this, the tanks each contained a small fan to agitate the contents back into a measurable state. The number-two oxygen tank had been damaged during its pre-launch inspection process. An attempt to empty it had resulted in the inside of the tank being subjected to extremely high temperatures, which in turn damaged the Teflon insulation on the wiring leading to its stir fan. When the time came during the mission to activate the fan and stir the tank contents for measuring, power passing through the damaged wires caused a spark, igniting the Teflon insulation, which burned rapidly in the oxygen-rich environment, which in turn pushed the pressure and temperature inside the tank quickly to and past its structural limits. The tank very quickly exploded.

In Ron Howard's Apollo 13, the effect is immediate and dramatic, with the spacecraft shimmying around like a drunk Vegas dancer, but in reality the crew only heard a dull "bang" sound. It was several minutes before they realized the problem was serious, with the spacecraft's oxygen supply slowly venting out into space. The world's attention quickly focused on the mission, and the "routine" trip to the Moon became a spectacle. The death of another Apollo crew—just three years after the Apollo 1 fire which killed Ed White, Roger Chaffee, and Gus Grissom—would likely have spelled an end to Project Apollo and potentially NASA's entire manned program.

The story has been told and retold in great detail—in fact, Sy recommends the IEEE's three-part article, "Houston, We Have a Solution" as the most complete and accurate retelling of the entire Apollo 13 explosion and its aftermath. That piece sheds a lot of light on the process of troubleshooting the damaged spacecraft, and it also discusses how controllers looked for problems. The extensive mission simulations the controllers went through fixated them on finding issues within the vehicle's instrumentation and how it reported back to ground, rather than physical damage, explosions, or holes. This fixation at first sent them down the wrong track for Apollo 13's very physical problem. The initial assessment of the Apollo 13 incident mirrored that of Apollo 12's lightning strike: something was clearly very, very wrong, but so many parameters were showing up off-nominal that it didn't seem possible the failures could reflect an actual mechanical, physical problem.

Gender disparity

I've been saying "he" throughout this article when referring to flight controllers, and that's partly out of convention and partly by design. There were no female flight controllers working in the MOCR during Gemini and Apollo; it wasn't until 1972 that a woman was included on the roster, and then it was as a back-room staffer (though that person, Dr. Carolyn Huntoon, later went on in 1994 to become the first, and so far only, female director of the Johnson Space Center). After that brief appearance in 1972, the next woman to hold a flight controller position was Dr. Bonnie Dunbar, who served as the Guidance and Navigation controller in 1979 on the Skylab program before entering the astronaut corps in 1981.

Female flight controllers became more common during the Shuttle program, but it wasn't until 1991 that the first woman, Linda Ham, would sit at the flight director console.

It's not that there was any kind of ingrained culture of conscious misogyny at NASA—at least, no more than at any other engineering-centric business in the 1960s and 1970s. The perception, which was either borne out by reality or which drove reality, was that engineering was a "hard" discipline and women were generally interested in "softer" pursuits. The most striking sign of the times is the bathroom layout for the MOCR floors in Building 30, which speaks louder than any statement of exactly what the intended gender mix was.

Sy's first call to Flight Director Gene Kranz was, "We may have an instrumentation problem, FLIGHT." In the IEEE article, Sy is quoted as later reflecting that this call "... was the understatement of the manned space program. I never did live that down."

However, those same simulations imparted an intimate knowledge of the Apollo spacecraft, down to its individual circuits. Sy described a typical "sim," highlighting the deep level of systems knowledge a flight controller and his back room team were expected to have. "One of the things the sim guys like to do is fail a telemetry gate, which would be a solid state chip that would pass through five or six parameters. We had drawings of all of that, and so what they would do is fail one of those gates and we'd look for those five or six parameters and we'd say 'Ah, it's that one', that particular gate, and we'd know what we'd lost." The controllers had to have near-total familiarity with the schematics of the systems they controlled, down to understanding where each circuit went, and that level of familiarity can only come through long hours of drills and simulations. That familiarity is what let Sy articulate the steps necessary to stop its bleeding oxygen out into space, once the realization dawned on him that Apollo 13's problems were manifestly physical.

The exploding oxygen tank had damaged the Service Module's fuel cells, which generated electricity for the spacecraft by combining oxygen and hydrogen. The oxygen from the other tanks was leaking through the damaged fuels cells out into space. Isolating them from the oxygen supply would therefore stop the leak. In Ron Howard's film, once controllers realize the scope of the problem, Sy Liebergot (again, played by Howard's famously odd-looking brother, Clint) informs the flight director the only way to stop the leak is to close the valves on the connections between the hydrogen and oxygen tanks and the fuel cells—the "REAC valves." Mission rules stated that the Apollo spacecraft needed at least two functioning fuel cells to generate the required amount of power to successfully accomplish the mission, so permanently disabling two fuel cells—"The whole smash," Tom Hanks says, misquoting what Lovell says in the transcripts—meant Apollo 13 would not be landing on the Moon.

The moment is treated with a tremendous amount of gravity in the film, with much soulful acting on the part of Hanks as mission commander Jim Lovell. In order to clue the audience in that the valve closure meant the mission was over, he looks despairingly at his crew and quietly states, "We just lost the Moon."

Enlarge/ This plaque, featuring one of the mirrors from Apollo 13's Lunar Module Aquarius, hangs on the wall in MOCR 2 today.

Photo by the author

Sy points out that Ron Howard and Tom Hanks took tremendous liberties with the film, which Ron Howard has also acknowledged. "I only asked for one fuel cell," Sy says, where in the film they immediately shut down two. "We didn't allow ourselves to believe that both fuel cells were dead... My request was to close the reactant valves to fuel cell three, only."

The request to disconnect fuel cell one didn't come until nearly a half-hour later, when it became clear that the oxygen leak hadn't been contained. This is reflected in the mission transcripts, with the order to disconnect the first fuel cell being transmitted at Mission Elapsed Time 02:08:57:27 (that is, two days, eight hours, 57 minutes and 27 seconds after launch), and the call to disconnect the second not arriving until almost 20 minutes later at MET 02:09:15:04. Entertainment often takes priority over historical accuracy, because history doesn't usually fit the neat dramatic beats which storytelling requires.

The EECOM desk, manned by Sy Liebergot and John Aaron and others, was absolutely essential to the safe return of Apollo 13. Sy was quick to downplay his role in the Apollo 13 crisis: "I didn't save anything—I just didn't get up and run!" In spite of his modesty, his role in keeping the crew alive is very clear, and it highlights the importance of the flight controller process in general and EECOM specifically.

"It's just not there"

But wait, there's more!

Want to know even more about MOCR 2? Check out the companion piece, Apollo Flight Controller 101, for a station-by-station description of every single console, including diagrams and button callouts!

Sy was involved after Apollo with the Shuttle program, and in 1979 he spent time participating in planning and design work on an early space station concept which would have functioned as a low Earth orbit transportation and construction node for manned missions to Mars and other destinations. The work was eventually supplanted by the ramp-up of Space Station Freedom, which itself was repeatedly scaled back and eventually given life as today's International Space Station (though vastly reduced in size and scope from the original plans).

I've written before on NASA's mission, and Sy spoke his mind freely as we neared the end of our interview. He sees the detrimental effect a lack of vision and program direction has had on the agency. "I do a lot of lecturing," he notes, "And during Q&As people will say, 'Well, you know, we've got... Orion, and we have the SLS,'" referring to Lockheed's Orion spacecraft currently in development, and the Space Launch System heavy-lift rocket being designed to carry it (as well as large cargoes) into orbit.

"Yeah, so?" Sy shakes his head. "They're two separate entities that could get canceled at any time. There's no umbrella project or program to encompass that. We're talking about a mission to Mars, and it's just not there."

As we drove away from the center back toward Building 110 to sign out, I asked Sy about what one does after something like Project Apollo. He painted a sketch of an agency in transition in the mid-to-late 1970s, shifting from a functional bureaucratic monster more and more toward a moribund bureaucratic monster. The career path within NASA for a flight controller wasn't really clear; talk of promotions and raises, even for civil servants, wasn't high on management's radar. NASA's rush to meet John Kennedy's end-of-the-decade lunar challenge and the subsequent Project Apollo flights were all-consuming. Today, things are of course different. I'm friends with no small number of government employees, and career planning is a continual activity. The flight controllers of the Apollo era were caught up in the present, so much so that it was difficult to see the future.

Most of the Apollo flight controllers were in their early-to-mid thirties when they manned their consoles. Gene Kranz was 32 when he sat his first shift as FLIGHT in 1965; Sy Liebergot was exactly my age, two months past his 34th birthday, when Apollo 13's oxygen tank exploded in 1970. The people who sat in MOCR 2 and guided Project Apollo to the lunar surface probably couldn't conceive of a future where space would be as peripheral a concern as it is among today's politicians and decision-makers. It is a heartbreaking thing to sit among the MOCR 2 consoles, which look almost prehistoric in their construction and ergonomics, and know that we once went so far with so little. Now, even though the laptop I brought into MOCR 2 with me has the processing power and memory of a thousand Apollo mainframes, no humans venture beyond low earth orbit, and MOCR 2 is a reminder of where we have been and where we are unlikely to ever go again.

Promoted Comments

Cathedral isn't an unreasonable comparison. If you were a child then, it could have been the most important thing you ever watched adults do. It was a welcome respite from things like riots, civil rights protests, the Viet Nam war, and price controls. The picture of the blue Earth rising over the grey horizon of the Moon might be the most significant photo ever taken. I'd probably burst into tears if I ever entered the MOCR.

Kennedy's speech at the Rice football stadium declares the Moon Shot in an almost cavalier manner. I don't think we're "unlikely to ever go again". If something crops up out there and we have to check it out, I'm sure new Sy Leibergots will be ready to help make it happen.

Look at the pic of the Super EECOM. Jersey Shore contestants and tone bending starlets would pass him by with a frown at most. But that pic will be seen in a hundred years and no one will know who the other people are.

Lee Hutchinson / Lee is the Senior Reviews Editor at Ars and is responsible for the product news and reviews section. He also knows stuff about enterprise storage, security, and manned space flight. Lee is based in Houston, TX.